This application is based on and claims priority under 35 U.S.C. xc2xa7119 with respect to Japanese Application No. 2000-398574 filed on Dec. 27, 2000, the entire content of which is incorporated herein by reference.
This invention generally relates to an electrically controlled device. More particularly, the present invention pertains to a disturbance compensation control device that restricts the periodic disturbance generated by a periodic compensation control and applied to an electrically controlled device.
A known type of disturbance compensation control system is described in Japanese Patent Publication No. 2566033. This known system controls the control object, for instance an electrically driven motor, by way of a feed back control system using the difference (control tolerance) between a target rotation speed and an actual rotation speed. Further, this known system estimates a disturbance to the motor and effects repetition compensation control with respect to the estimated disturbance to eliminate periodic disturbance.
According to this known control system, because the motor is unstable at starting, the repetition cycle of the disturbance is also unstable. If this unstable disturbance is applied to the repetition compensation control, the accuracy of the motor operation with respect to the target speed will be decreased. This is particularly so in the case of apparatus having a short interval operating duration. Also, the delay with respect to the repetition compensation control will be worth to the stable control.
A need thus exists for a disturbance compensation control system which performs appropriate repetition compensation control and is not as susceptible to the same drawbacks and disadvantages as those noted above.
In light of the foregoing, one aspect of the invention involves a disturbance compensation control system which restricts periodic disturbance to a motor. The disturbance compensation control system includes means for calculating a target rotation speed of the motor, means for calculating an actual rotation speed of the motor, and means for calculating a difference between the target rotation speed of the motor and the actual rotation speed of the motor. A repetition control unit receives the calculated difference between the target rotation speed of the motor and the actual rotation speed of the motor, and repeatedly applies a compensated value to the calculated difference. The compensated value applied by the repetition control unit during initial starting of the control object is based on a zero value of the difference between the target rotation speed of the motor and the actual rotation speed of the motor.
According to another aspect of the invention, a disturbance compensation control system which restricts periodic disturbance of a control object includes means for calculating a target control condition of the control object, means for calculating an actual control condition of the control object, means for calculating a difference between the target control condition of the control object and the actual control condition of the control object, and a repetition control unit which receives the calculated difference between the target control condition and the actual control condition, and applies a value to the calculated difference, with the value applied by the repetition control unit during initial starting of the control object being based on a zero value of the difference between the target control condition and the actual control condition.
According to another aspect of the invention, a disturbance compensation control system which restricts periodic disturbance of a control object includes means for calculating a target control condition, means for calculating an actual control condition, means for calculating a difference between the target control condition and the actual control condition, and a repetition control unit which receives the calculated difference between the target control condition and the actual control condition, and applies a value to the calculated difference. The repetition control unit includes a phase converter.